Japanese Patent Laid-Open Publication No. 2008-94227 and its counterpart U.S. Patent Publication No. 2008/0088167 disclose a vehicle seat reclining device that includes a portion affixed to the vehicle body, which cooperates with a lock member affixed to a tiltable seatback of a vehicle seat so as to permit the seatback to be selectively locked in a stepwise manner in a series of tilted positions. The vehicle seat reclining device comprises a rail, a slider and a lock apparatus.
The rail extends linearly along a central axial line and is affixed to the vehicle body so as to be tangential to a curved path traced in space by the lock member as the seatback tilts. The slider is slidably attached to the rail and pivotably supports a striker. The striker engages with the lock member on the seatback. The lock apparatus comprises two protruding portions that respectively engage in notch portions of the rail and lock holes of the slider so as to prevent the slider from sliding along the rail. The protruding portions can be retracted from the rail and the slider in order to permit the slider to slide along the rail.
Such a vehicle seat reclining device employs a linear or straight rail and a slider that slides along the straight rail. Therefore, manufacturing costs can be reduced as compared to a vehicle seat reclining device that employs a slider that slides along an arched or curved rail.
However, when the slider slides along a linear rail due to the seatback being tilted, the lock member traces or moves in space along an arched or curved path while the slider moves along a linear path, whereby a deviation between the two paths occurs. Therefore, the striker must pivot on the slider in order to absorb the deviation. This pivotability also reduces the effect of tolerance flaws that would make it difficult for the slider to slide along the rail when the seatback is tilted.
However, it is difficult to achieve a smooth tilting action of the seatback while simultaneously achieving a reduction in manufacturing costs with such a vehicle seat reclining device.
More particularly, the above-described vehicle seat reclining device is configured such that the striker is pivotably supported on the slider. It is therefore difficult to reduce manufacturing costs as compared to a more common configuration, in which the striker is fixedly attached to the slider. Moreover, since it is difficult to construct both a pivotable support and a fixed attachment between the striker and the slider, when the slider slides along the rail, rattling or other noises readily occur in the area around the pivot shaft of the striker and the slider. This makes it difficult to realize a smooth tilting of the seatback.